pedrolopesme/s3tools

package utils

import (
    "fmt"
    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/service/s3"
    "github.com/aws/aws-sdk-go/service/s3/s3manager"
)

type s3BufferedFile struct {
    Bucket string
    Path   string
}

// GetBucket returns file path
func (f s3BufferedFile) GetBucket() string {
    return f.Bucket
}

// GetPath returns file path
func (f s3BufferedFile) GetPath() string {
    return f.Path
}

// GetBufferedContent creates a S3 session and reads the content
// of a file writing it into a buffer.
func (f s3BufferedFile) GetBufferedContent() (buf []byte, err error) {
    if f.Bucket == "" {
        fmt.Println("Aborting due to empty bucket")
        return
    }

    sess := session.Must(session.NewSession())
    downloader := s3manager.NewDownloader(sess)
    awsBuffer := &aws.WriteAtBuffer{}

    _, err = downloader.Download(awsBuffer,
        &s3.GetObjectInput{
            Bucket: aws.String(f.Bucket),
            Key:    aws.String(f.Path),
        })

    if err != nil {
        return
    }

    buf = awsBuffer.Bytes()
    return
}

// newBufferedFile returns a concrete type of s3BufferedFile
// properly initialized. Following recommendations found at
// https://github.com/golang/go/wiki/CodeReviewComments#interfaces
func newBufferedFile(bucket string, path string) s3BufferedFile {
    return s3BufferedFile{
        Bucket: bucket,
        Path:   path,
    }
}